Diagnostic or angiographic catheters for introducing a radiopaque dye into a blood vessel for diagnosing a condition of the blood vessel are well known in the prior art. A diagnostic catheter is an elongated flexible member having a passageway for delivering a radiopaque dye under pressure from a source outside the patient to a diagnostic site within a patient. A typical use of such a dye is for imaging a region of the blood vessel on a diagnostic imaging screen.
A typical diagnostic procedure begins with an incision formed in the patient where the diagnostic catheter is to be inserted into an artery. A percutaneous introducer is inserted into the incision to form a passageway into the subject vasculature. The catheter is pushed through the introducer into the vasculature. If only a small diameter catheter is inserted, it is advantageous to use a small introducer so the incision is also small.
In many diagnostic procedures the introducer is inserted into the vasculature of the patient at an access site spaced a significant distance from the intended delivery site for the radiopaque dye. As an example, when conducting a study of blood flow through the heart, the catheter may be inserted into the femoral artery in the groin and routed up the aortic artery over the aortic arch to the region of the heart. Since this insertion technique is a well known techique, specially shaped catheters configured for this procedure are commercially available from a number of sources.
Diagnostic catheters are categorized by their fluid delivery capacity. This capacity is dependent on the cross sectional area of the interior of the catheter available for fluid delivery. A special classification system has been developed to describe catheter size. For example, a french 4 catheter (Fr 4) is a catheter having an outer diameter of approximately 1.32 millimeters, where one french is the equivalent of one-third of a millimeter. Percutaneous introducers are also characterized using this system. The dimension of the introducer referenced using this system is the internal diameter of the introducer passageway through which the catheter passes. Therefore, a french 4introducer (Fr 4) refers to an introducer with a passageway having an inner diameter of approximately 1.32 millimeters with sufficient tolerance to receive up to a Fr 4catheter.
Certain diagnostic procedures require high flow rates to produce adequate images. This flow rate requirement for diagnostic catheters limits the ability to reduce the interior cross-sectional area and use a smaller introducer. For example, certain diagnostic procedures require a volume of fluid delivered by a Fr 8 catheter, requiring at a minimum a Fr 8 introducer. It is a goal of the present invention to minimize the size of the incision required to access the patient's vasculature while delivering a volume of diagnostic fluid which has previously required a larger incision and a larger introducer.
Certain procedures also require the deployment of instrumentation or devices, such as stents, in addition to diagnostic fluid. Typically, such instrumentation and devices are deployed through the interior of an elongated flexible member, or guide catheter. Conventional guide catheters must be large enough to accommodate the instrumentation and deliver a sufficient volume of diagnostic fluid through the same passageway, These requirements for traditional guide catheters limit the ability to reduce the interior cross-sectional area of the catheter and use a smaller introducer. It is another goal of the present invention to reduce the size of the guide catheter and the size of the required incision at the access site while delivering a sufficient volume of diagnostic fluid.